1. Field of the Invention
The present invention relates to disc players for writing information in a disc such as a compact disc (CD) or a digital versatile disc (DVD) and/or for reading information written therein. In particular, the preferred embodiments of the present invention relate to a car-mounted disc player with a drive unit that is elastically supported on a chassis through an elastic member interposed therebetween. Further, the preferred embodiments of the present invention relate to the use of anti-vibration measures for switching the drive unit between a locked state and an unlocked state with respect to the chassis.
2. Description of the Related Art
A car-mounted disc player for use with a disc such as a CD or a DVD may be susceptible to problems caused by external vibrations. For example, a disc player may contain a drive unit having an optical pickup, a turntable and so forth mounted that is fixedly supported on a chassis. In this instance, if an external vibration is exerted directly on the optical pickup and the disc during play (during writing or reading information), the problem of sound skipping or the like may result. In order to prevent such a problem, a car-mounted disc player is usually designed such that the drive unit is elastically supported on the chassis through the use of elastic members such as dampers so as to prevent an external vibration or shock from being exerted directly on the drive unit and the disc during play. More particularly, the car-mounted disc player of this type is equipped with a lock mechanism which switches the drive unit between a locked state and an unlock state with respect to the chassis. In this regard, during play for writing or reading information in a state in which the optical pickup is set so as to face the disc placed on the rotating turntable, the lock mechanism holds the drive unit in the unlocked state of being elastically supported on the chassis, and during disc-transfer for inserting or ejecting the disc, the lock mechanism holds the drive unit in the locked state with respect to the chassis by constraining the drive unit. With this arrangement, anti-vibration measures such as dampers prevent a problem of sound skipping and the like even when an external vibration or shock is exerted during play. Further, by defining the positional relationship between the locked drive unit and a disc slot formed on the front surface of the chassis, an operation of inserting or ejecting the disc can be performed without any problems.
This car-mounted disc player has a structure in which a pair of sliders moving back and forth driven by a motor are disposed at both sides of the chassis and the lock mechanism and a clamp mechanism for bringing a damper in or out of contact with the disc are activated in accordance with an advance or retreat position of the two sliders. These two sliders move in synchronization with each other by means of a link mechanism or the like. In a standby state in which the disc is not loaded, the damper is held at an upper position where the damper is brought out of contact with the turntable and the drive unit is brought in the locked state. Also, when the disc is transferred to a playing position of the disc player, the damper moves down so as to press the disc on the turntable and the drive unit is brought into the unlocked state from the locked state.
The car-mounted disc player of this type may be used as a car-mounted navigation apparatus in addition to as an apparatus for playing back a music disc or the like, and the disc player is sometimes shipped in a package set together with a disc (CD-ROM, DVD, or the like) having map information written therein. In this case, although there are provided two systems for shipping the disc player; the one in an ejected state in which the disc is ejected from the disc player during transport and the other in a chucked state in which the disc is loaded in the disc layer during transport, the other system is usually employed in order to reduce the volume of the packed disc player. However, according to the foregoing related art, in the chucked state in which the disc placed at the playing position is clamped by the damper and the turntable, since the drive unit is brought into the unlocked state from the locked state and is elastically supported on the chassis, when a strong external vibration or shock is exerted on the disc player during transport, the disc hits against a stationary component such as the chassis and hence gets damaged.
Also, in the car-mounted disc player of this type, especially in the disc player for a DVD, the tilt of a laser beam emitted from the optical pickup must be adjusted at the final assembling stage of the disc player while the disc is rotating. However, since the drive unit remains in the unlocked state while the disc is played, a adjustment of the tilt of the optical pickup or the turntable is very difficult to the need to press the elastically supported drive unit by using, for example, an adjusting jig inserted in the chassis.